Control system for a line printer having an endless type carrier.

摘要

This control system for a multispeed/multipitch line printer basically comprises two read/write memories called the Band Image Buffer (19) and the Print Line Buffer (17). The Band Image Buffer (19) is loaded with the character image of the print band or chain (10) and can be visualized as an electronic band running in synchronism with the type carrier (10). The Print Line Buffer (17) is loaded with a line of data to be printed. Both buffers (17, 19) are read during each option time of a print subscan, their contents are compared in a comparator (47)-which controls the hammer firing circuits (51, 53)-, and their respective address registers (23, 22) are modified to a new value at the end of each subscan. A control bit is stored in a check buffer (20) to detect the end of each subscan. Comparison of the contents of the Band Image and Print Line Buffers (19, 17) continues until the control bit is detected signifying that a Band Image Buffer correction cycle followed by a Print Line Buffer correction cycle should be performed.